sugar glider kept losing weigt

Question
Hello,
Here is my sugar glider's profile：
Sex: female   Age: over three years   History: healthy   Food: fish,corn,fruits ,chicken, calcium
Recently, she kept losing weight, from 180g to 100g and it took about 4 months.I'm worry about this because the same thing happened to the other one six months ago and led her to death.She is still active and has good appetite but becomes slender. Besides, her fur isn't shiny as usual.I wonder whether calcium deficiency caused it because we used to feed her too much corn and chicken but didn't offer enough calcium. I'm trying to feed her food with sufficient nutrition. Hope she won't keep losing weight.   
I want to know what I can do for her. And, have you ever seen the same cases? Will she die?

Answer
Well sadly I can say it is likely the diet. Corn, as well as cat and dog food, should never be fed to a glider. It is high in phosphorus and will kill the glider. Chicken should be fed very sparingly. A gliders diet should consist mainly of a staple diet of a food such as monkey pellets, gliderade, bugsnberries and fresh fruits. As well as insects periodically and calcium.

Gliders are very sensitive, especially emotionally and with their diets. And I can say with confidence that the diet, as well as the living situation, is the cause for the health decline.

No glider could be healthy eating the listed items, they HAVE to have the items I listed, people always think it is funny when I say they are more needy than a newborn, but it is true.

If the glider is living a longer then it will not thrive. They need groups to be happy. I would start by quickly changing the diet, or yes, this one will also most likely die. As it is just not getting the proper nutrition that it's body was intended to get.